Immunotoxicity of organo-halogenated contaminants in Norwegian white-tailed eagle Haliaeetus albicilla nestlings
Marine top predators are characterised by high levels of biomagnifying pollutants, such as organo-halogenated contaminants (OHCs). OHCs are man-made chemicals and many of them have been found to induce detrimental effects to wildlife. Marine top predators therefore represent good biological models to assess the impact of anthropogenic pollutants on wildlife health. In this study, we used a sentinel top predator of the Norwegian marine fauna: the white-tailed eagle (WTE: Haliaeetus albicilla) for testing new tools to understand how OHCs can induce physiological stress and impair the immune system (also known as immunotoxicity). We predicted that higher contaminant levels in WTEs were associated with a reduced immune defence and higher stress, compared to less contaminated individuals. To assess the immunotoxicity of OHCs in WTEs, we performed a technique called leukocyte coping capacity (LCC). LCC represents an integrated measure of the immunocompetence and ability to cope with stressors. More precisely, LCC is an in vitro immune challenge to assess the innate immune response as the capacity of leukocytes to produce a respiratory burst (i.e. the release of reactive oxygen species). Individuals with a higher LCC have a greater potential to produce a respiratory burst, and physiologically, are better able to respond to immune challenges following stress. The LCC analysis was performed in the field on WTE nestlings (n = 84) in Northern Norway over two breeding seasons (2017-2018). In addition, leukocyte profiles of nestlings were analysed, as a measure of physiological stress in vertebrates. The results showed clear gender and inter-year differences in LCC responses among WTE nestlings. We also found increased stress levels in chicks in poorer body condition. In accordance to previous studies, perfluoroalkyl substances (PFAS) dominated the total plasma contaminant load of the WTE nestlings. There were significant correlations between some PFAS and LCC of WTE nestlings, indicating a potential immunotoxic effect of some OHCs. We suggest that LCC might be used as a tool to assess sub-lethal effects of OHCs on the innate immune system, and in combination with other health assessments such as leukocyte concentrations, contribute to assess the physiological status of nestling white-tailed eagles.
PublisherUiT Norges arktiske universitet
UiT The Arctic University of Norway
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